The present invention relates primarily to optical systems and the method of making the same where laminated light transmitting plates are made capable of reflecting from one side of the laminate a three-dimensional image fixed in one of the plates while transmitting coherent light waves through the entire body of the laminate.
An eyeglasses lens with somewhat similar results, but in only two dimensions, is the subject of prior Letters Patent, but the present invention offers not only the reflective image with three-dimensional and bas relief depth but accomplishes the result with greater simplicity and effectiveness than the prior art.
The most pertinent prior art on the subject appears to be U.S. Pat. No. 4,715,702 disclosing a structure for providing a decorative pattern over the surface of sunglasses. The structure combines a positive, two-dimensional, decorative pattern imprinted on a first lens layer, a reflective layer, and a third layer incorporating a negative decorative pattern. The decorative pattern is apparent to an observer as a flat image, but the negative pattern cancels the image for the wearer who then sees only a uniform color or hue that does not interfere with his vision or cause a distraction.
Other patents which disclose eyeglasses where characters or symbols are applied to the lens surfaces are U.S. Pat. Nos. 4,329,378; 4,145,125 and 2,281,101. The disclosures of these patents are not considered pertinent to the present invention except for a vague similarity of purpose.
Laminated and coated lenses for preventing glare, such as found in U.S. Pat. Nos. 2,675,740; 2,230,009 and 4,320,939 share some of the structural aspects of this present invention but do not teach its methods or the same details of structure.
The invention also relates to the manufacture of colored optical glass. Such glass is frequently used as colored filters or as architectural glass.
In the past, color in glass has been produced in several ways. For example, color can be achieved by the choice of raw materials used in the glass-making solution. For example, copper or cobalt compounds are used to produce blue glasses.
Color can also be achieved by separation of finely divided particles of material from the clear melt in the glass melting furnace. For example, using this technique, gold, copper, or cadmium sulfide produce ruby glass.
Both of the above techniques require precise batch formulations of raw materials. The coloring process also occurs during the melting step associated with glass formation. Thus, the glass, in practical terms, is colored in large batches. Often, the exact hue and saturation desired is difficult to achieve as well as predict.
Colored optical glass is frequently used as colored filters in optics and photography. Colored filters include filters made in several forms, including glass filters and gelatin film.
Colored glass filters are made using the processes described above for coloring glass. Thus, the glass is colored in large batches in the melt process and exact hue and saturation are difficult to achieve.
Dyed film filters are made of dyed gelatin, cellulose esters, and other plastics. The greatest variety is in the form of gelatin film. These filters are prepared by coating a previously determined thickness of gelatin containing the necessary dyes upon plate glass and, after drying, stripping the gelatin film off the glass. Gelatin filters mark and scratch very easily and thus are frequently cemented between flat plates of glass. Again, as the gelatin is dyed in batch form, the exact hue and saturation is hard to predict.
Glass can also be painted a desired color although the inherent unevenness of a painted layer can result in optical distortion. This is particularly true when the paint is applied by a spray method, as it is difficult to achieve a uniform coat.
Glass coatings are also well known and, in particular, it is known to provide an element with a layer of fluorescent material to absorb certain wavelengths of light. Such is shown in U.S. Pat. No. 4,320,939 to Mueller. The fluorescent coating is applied by a solution or coating composition, or is contained in a transparent sheet or film. The Mueller reference avoids reflection problems associated with distortion by keeping the fluorescent layer sufficiently thin.
It is therefore the primary object of this present invention to provide an optical system that transmits coherent undistorted light images while at the same time producing a three-dimensional image to an observer by means of the light reflected from an interior contoured surface of one of the layers of the system assembly.
A second object of the invention is more universal, actually leading to the first objective. That objective is to provide a method whereby a scratched or otherwise surface-distorted light transmitting plate may be reconstituted, without surface reclamation or alteration, to pass coherent light waves without the scattering effect produced by the surface distortion. The light transmitting plate may be in the form of a multi-layered structure, wherein one of the layers of the structure has the scratched or distorted surface.
It is another object of the invention to provide a method for contouring the surface of a hardenable plastic layer and then securing the hardenable layer to a light-transmitting plate. The hardened layer and light-transmitting plate are part of an optical system that transmits coherent undistorted light images while at the same time producing a three-dimensional image to an observer.
A further object of the invention is to provide a novel lens assembly that substantially eliminates secondary light reflection within the lens without the use of outside surface anti-reflective coatings, at least over the portion of the lens having a light scattering surface formed into the interior of the lens system for image reflection purposes.
A further object of the present invention is to provide a lens structure of the type described which lends itself to construction from plastic components which can be dipped to create gradation tinting, especially for use when the lens is applied to sunglasses.
It is an additional object of the instant invention to provide colored optical glass in which the hue and saturation of the color can be controlled.
It is a further object of the invention to provide colored optical glass wherein each desired piece can be individually colored using a spray paint technique with minimal optical distortion.
It is an additional object of the invention to provide a technique for substantially removing the optical distortion created when plate glass is painted with transparent paint.
Other and further objects, features and advantages of the invention will become apparent upon a reading of the detailed description of a preferred form of the invention which follows. It will also become apparent that the optical system of the present invention, while useful with lenses, can be employed in a large number of different applications which are not lens related, including building windows, vehicle windows, semi-transparent mirrors, closed circuit television discrete enclosures, furniture tops and displays.
The detailed description of the invention is directed toward applying the invention to sunglasses.